BOSTON -- This is the reason it's hard to take the Nets seriously at times, and just the latest numbing example.

They were in the midst of one of their best stretches of the season, going over the .500 mark for the first time by beating a pair of likely playoff-bound teams in the Bulls and Grizzlies. It put them on the brink of matching their longest winning streak of the season. All the Nets had to do was upend the Celtics, who had gotten pasted by the Warriors two nights earlier.

Latest Nets stories

Instead, the Nets trailed from the opening tip to the final buzzer, a disheartening display for a team that thought it finally had discovered its mojo.

The Nets had a rough shooting night and lost to the Celtics, 91-84, Friday night at TD Garden, ending their winning streak at four and sending them back to the .500 mark.

"Yeah, I mean this is a tough one," said Deron Williams (20 points, four assists). "The way we've been playing, we've been playing well, had some good wins against some good teams, and to come out here and drop this one is definitely frustrating."

Almost as bothersome as clanking shots, particularly from beyond the arc. The Nets (30-30) shot 4-for-30 from three-point range, misfiring on their initial 17 tries. They didn't knock down their first one until Williams swished a three with 6:27 left in the third quarter to bring the Nets within 66-55.

But the Celtics answered with a 12-3 spurt to grab an 82-71 lead early in the fourth. No way the cold-shooting Nets, who were outrebounded 51-28, could erase that deficit, not even against a team that had 28 turnovers.

"It's tough because when April comes, these are the games that you are going to look back on and they are going to hurt," Johnson said. "So this is definitely a game that we needed and we've got to be able to put teams like this away."

"I think every loss at this point really hurts, it stings, because we know how close the Eastern Conference race is," said Paul Pierce, who wasn't much of a factor with 10 points in his second game here wearing Nets garb. "The difference between one or two games can mean a high seed or a low, low seed. So every game counts at this point. You've only got four or five weeks left in the season, and we've got to take advantage of the teams that are under us. Tonight we didn't do that."

Subscribe to Newsday’s sports newsletter

Receive stories, photos and videos about your favorite New York teams plus national sports news and events.